Iron in human diet
The iron content of the body is 4-5 g. Most of it present in the hemoglobin (blood) and myoglobin (muscle tissue) pigments.
The metal is also present in a number of enzymes (peroxidase, catalase, hydroxylases and flavine enzymes), hence it is an essential ingredient of the daily diet.
The iron requirement depends in the age and sex of the individual, it is about 1.5-2.2 mg/day. Iron supplied in the diet must be in the range of 15 mg/day in order to meet this daily requirement.
The large variations in intake can be explained by different extents of absorption of the various forms of iron present in food (organic iron compounds vs. simple salts).
The most utilizable source is iron in meat, for which the extent of absorption is 20-30%. The absorption is much less from liver (6.3%) and fish (5.9%) or from cereals, vegetables and milk, from which iron absorption is the lowest (2.0-1.5%).
Eggs decrease and ascorbic acid increases the extent of absorption.
Bran interferes with iron absorption due to the high content of phytate. Apparently, the absorption of iron present in food is in a healthy organism regulated by the requirement of the organism.
Nevertheless, in order to provide a sufficient supply of iron to persons who require higher amounts (children, women before menopause and pregnant or nursing women), cereals (flour, bread, rice, pasta products) fortified with iron to the extent of 55-130 mg/kg are recommended.
Extensive feeding test with chickens and rats have shown that FeSO4 is the most suitable form of iron, but ferrous gluconate and ferrous glycerol phosphate are also efficiently absorbed.
Two food processing problems arising form mineral fortification are the increased probability that oxidation will occur and in the case of wheat flour, decreased baking quality.
Generally, iron is an undesirable element in food processing; for example, iron catalyzes the oxidation of fat or oil increase turbidity of wine and as a constituent of drinking water, its support the growth of iron requiring bacteria.
Iron in human diet
